汶川地震重灾区武都三家地滑坡治理工程效果分析

An analysis of the treatment effect for Sanjiadi landslide in Wudu county, a heavy disaster area during the Wenchuan earthquake

甘肃陇南市武都区是5·12汶川8级地震重灾区,地震引发了大量滑坡和斜坡变形破坏,其中在汉林沟三家地老滑坡前缘引发了连续分布的H1,H2,H3三处滑坡,并堵塞沟道,是汶川地震在甘肃省境内引发的规模最大的地震滑坡.老滑坡后缘出现大规模贯通裂缝,严重威胁滑坡体上三家地村1 732名村民的生命财产安全和灾后重建工作,也为汉林沟泥石流提供了丰富的松散固体物质.基于大量的调查、勘探和室内外试验,在综合分析滑坡特征和稳定性基础上,针对性的采取了前缘回填反压、地表排水、裂缝和落水洞夯填等综合治理措施.对治理效果进行了有限元(FEM)数值模拟,通过对比施加前缘反压工程前后滑坡的位移、最大剪应变和稳定系数的变化来分析治理工程效果.经过监测,滑坡处于稳定状态,证明治理效果良好.

Wudu district of Longnan City was one of the heavy disaster areas during the 5 · 12 Wenchuan 8.0 magnitude earthquake and numerous landslides and slope deformation disasters were induced by the earthquake. Specifically, the earthquake triggered three continuous distribution landslides （number H1, H2, H3） in the forepart of the ancient Sanjiadi landslide in Hanlin valley. These landslides also were of the largest size of earthquake landslides in Gansu Province during the earthquake. A large scale of cracks formed at the rear of the ancient landslide, producing rich loose and solid matter for debris flow; therefore people’s lives and property and post-disaster reconstruction work have been seriously threatened. According to a substantial investigation, prospection and experimental data as well as a comprehensive analysis of the geologic surroundings, sliding features and stability of Sanjiadi landslide, the landslide was treated with backfill compaction, surface drainage, fracture and ponor backfilling measures, which have controlled the landslide effectively and protected Sanjiadi village from further disasters. A numerical simulation for the reinforcement effect was carried out by using the finite element method. Through a comparison of the changes in the landslide displacement and of the stresses and safety factors before and after the reinforcement, the reinforcement effect was illustrated and proved to be successful by nearly one year’s displacement monitoring.